Gas turbine engine airfoils are subject to high steady state and vibration stresses during use. The resulting mechanical stresses tend to be particularly important at the root of the airfoils that is at the juncture between the airfoils and the associated supporting structure. Fillets have been used at the junction between the airfoils and the supporting structure to reduce stress concentration. Generally, the larger the fillet radius, the lower the stress concentration is. However, the radius of the fillets is limited by 1) the impact it might have of the flow performance of the working fluid being acted upon by the airfoils and 2) by the airfoil resonant frequency criteria. The design of the fillet is farther limited by the manufacturing constraints.
Accordingly, there is a need to provide a new. airfoil root fillet design and machining process.